1. Field of the Invention
The present invention relates to a door lock mechanism in which a door is opened by a door handle and locked by a key cylinder.
2. Background of the Invention
When a vehicle receives an impact from the side (called a side surface impact or side impact), opening or locking a door caused by the impact should be avoided.
Patent document 1 (Japanese Laid Open Patent No. S60-55672) discloses, for example, a protrusion part arranged on the inner side of a door outer panel, as a prior art for preventing a door from opening at the time of a side impact. According to this document, when the door outer panel is deformed towards the inside of the vehicle at the time of a side impact, the protrusion part arranged on the outer panel also moves, engages with an extension part of unlock lever (lift lever) of a door lock device, and thereby prevents unlocking.
Patent document 2 (Japanese Patent No, 4099745) discloses, for example, a bracket arranged immediately next to a door latch connected with a key rod linked to a key cylinder, as a prior art for door lock prevention at the time of a side impact. This bracket is attached to a latch cover or a door outer panel. According to this document, the bracket is deformed by the impact, thereby interposes the key rod and prevents the key rod from moving to a locked state.